#corals week

What's wrong with this picture? 

These two images show a reef in National Marine Sanctuary of American Samoa just months before (left) and after (right) a bleaching event. 

When we burn energy sources like gasoline and coal, we release carbon dioxide into the atmosphere. This carbon dioxide acts like a heat-trapping blanket, keeping heat from the sun close to the planet and warming the atmosphere and the ocean. Corals are sensitive to temperature: if the water gets too warm, they expel the colorful algae that they need to survive. This is called bleaching, and if it lasts long enough, the corals can die. 

But there are things we can do: by working with your community to curb your fossil fuel consumption and reduce other coral stressors, like pollution, you can help protect vibrant coral reefs! 

(Photo XL Catlin Seaview Survey/The Ocean Agency) 

Looking for a way to help corals stay healthy? Make sure you're using a reef-safe sunscreen or use Ultraviolet Protection Factor (UPF) sunwear! 

Several chemicals in traditional sunscreen can damage and kill corals, and are also harmful to green algae, sea urchins, fish, mussels, and dolphins. Even if you don't live near the ocean, when you shower, the chemicals in sunscreen may wash off and enter our waterways. So by making a small change in your sun protection, you can help support healthy coral reefs! 

(Photo: Olivia Williamson) 

Happy Corals Week! 

All week long, we'll be celebrating the beauty and importance of coral reef ecosystems around the world. Stay tuned for some coral-ly awesome facts! This colorful coral structure provides habitat for a variety of species in Florida Keys National Marine Sanctuary. 

(Photo: Greg McFall/NOAA) 

Every August, seven to 10 days after the full moon, the reef-building corals of Flower Garden Banks National Marine Sanctuary put on a fantastic spawning display, one of the most abundant displays in the entire Caribbean. 

Most scientists agree that these mass spawning events are designed to allow genetic mixing and dispersal of offspring over large distances. Plus, the sheer volume of the events allow for the fertilization and survival of a significant number of larvae despite the best efforts of predators! 

Learn more about the yearly spawning event here.

Corals are at the heart of many ocean ecosystems. 

For example, the extensive coral reefs of the Northwestern Hawaiian Islands are home to more than 7,000 marine species, one quarter of which are only found in the Hawaiian Archipelago! These lush ecosystems are protected by Papahānaumokuākea Marine National Monument. Here, a melon butterflyfish takes shelter in an Acropora coral. 

Can you name some of the other marine species that live in the reefs of Hawai‘i? 

Corals like this one in National Marine Sanctuary of American Samoa form the backbone of healthy ocean ecosystems. 

Coral reefs support more species per unit than any other marine environment, including some 4,000 species of fish! Corals also form the backbone of healthy human communities. They buffer shorelines from wave actions and prevent storm damage, they provide food and recreational opportunities, and even are the source of new medicines. 

What do corals do for you? 

Though they may look an awful lot like plants, corals are actually animals! 

Coral structures are made up of tiny individuals called polyps. At night, these polyps extend their tentacles to feed on tiny floating zooplankton. Look closely at this coral in Gray's Reef National Marine Sanctuary and you can see its tentacles reaching out! 

Can you name a more iconic duo than corals and their tiny single-celled algae partners?

Called zooxanthellae, these small algal cells provide food for corals by transforming sunlight into nutrients. Coral polyps use food that the algae leak out as an energy source to grow and flourish, like this reef-building community in National Marine Sanctuary of American Samoa! The algae also provide corals' brilliant colors. Because the algae are key to healthy coral reefs, this is also why we mostly find reef-building corals in waters that have adequate access to sunlight. 

 (Photo: The Ocean Agency/XL Catlin Seaview Survey)